X-RAY STUDY OF GLASSY BEHAVIOR IN C60 SINGLE-CRYSTALS

We observed the relaxation behavior of the X-ray diffraction intensity arising from the glassy phase transition in C60 single crystals for t he first time. The (7 10 0) reflection which appeared below about 160 K showed an anomalous cusp-type feature near 90 K. It was found that t his behavior strongly depended on the cooling rate of the specimen. In tensity relaxation of the reflection at 80 K at a cooling rate of 66 m K/s followed the single exponential law, I(t) is-proportional-to I0 (1 -exp(-t/tau)) with a relaxation time constant tau of 1.8 x 10(4) secon ds. These results strongly support those previously reported.